Process of flattening glass sheets



Patented June 17, 1924..

- eam rarest crate HARRY G. SLINGLUFF, OF MOUNT V'EBNGN, OHIO, ASSIG-NOE T0 PITTS BUEGH ELATE GLASS COMPANY, A. CORPORAIFIGN OF PENNSYLVANIA.

PROCWS FLATTENING GLASS SHEETS.

Application filed March 26, 1923. Serial No. 627,674.

To all whom it may concern:

Be it known that I, HARRY G. SLINGLUFF, a citizen of the United States, and a resident of Mount Vernon, in the county of Knox and State of Ohio, have made anew and useful invention in Improvements in Processes of Flattening Glass Sheets, of which the following is a specification.

The invention relates to a process for flattening glass sheets, particularly the partial cylinder sections, known as shawls, produced in the manufacture of window glass. Thes shawls, in some cases, constitute one third of the circumference of the cylinder, but ordinarily one half of such circumference. My application No. 621,182 sets forth a method of flattening such shawls and also the sheets produced in a sheet glass machine by assing them through a roller leer and permitting them to flatten of their own weight, but in some cases, the shawls will not entirely flatten of their own weight due to the uneven character of the cylinders from which they are cut and some mechanical pressure is required to make them flat enough for satisfactory glazing. The present application is directed toward the additional step of providing for the flattening of shawls which will not satisfactorily flatten in the process set forth in my application above referred to. One form of apparatus which may be employed for carrying out the process is illustrated in the accompanying drawings wherein: v

V Figure 1 is a longitudinal section through a kiln in which the process is being carried out. Fig. 2 is a longitudinal section on an enlarged scale through a portion of the Fig. 1 construction. And Fig. 3 is a transverse section through the leer.

Referring to the drawings, 1 is the arch of the kiln preferably curved as indicated in Fig. 3, and 2 are the side walls provided with suitable openings 3 for gas burners by means of which the necessary heat may be secured. 4 are a series of rollers mounted transversely of th kiln and driven by suitable gearing 5 (Fig. located outside of the kiln. The rolls are preferably about 4 inches in diameter and spaced on 8 inch centers. They may be made of materials specially designed to avoid marring the glass, such as nichrome or nickel or may b provided with carbon surfaces, but preferably they are made of cast iron having their surconditions.

faces white-washed or covered with a film of rust, as this is a relatively cheap construction and one which satisfactorily avoids marring when proper temperature conditions are observed in the kiln.

Above the rolls a are a series of flattening rolls 6, 7, 8, 9 and 10, the number of such rolls not being fixed, as such numbers may be increased or decreased depending upon These rolls are preferably constructed in the same manner as the rolls 4 and are preferably driven in the same manner. As indicated in Fig. 2, these rolls are spaced progressively closer and closer to the rolls-d.

' The kiln is shown as formed in four sections-by means of sub-divisions 11 and 12, and the total length of 45 or 50 feet is sufficient to secur proper flattening and annealing and permit of a reduction of temperature at the outlet end, such that the sheets may be easily handled as they emerge. A. satisfactory temperature for the first section of the kiln has been found to be about 1440 F. and the temperatures in the succeeding sections are successively lower, tapering down to about 200 F. in the last section. In flattening the cylinder sections 13, as indicated at the left-hand end of the kiln, these sections are placed'upon the rolls 4 with their convex sides down as indicated in Fig. 3. As the sections are fed along the rolls 4; in the first compartment of the kiln, they quickly becom heated to a temperature such that they loose their rigidity and settle down by their own weight to approximately a fiat condition. there is still some curvature due to the irregularity of the cylinder from which the shawls were cut, and in such cases, the rolls 6, 7, 8, 9, and 10 are brought into play to further flatten the sheet. In case the curvature is considerable, each .of the rolls from the first to the last may exercise a certain amount of flattening pressure, while in other cases, only one or two of the last rolls may touch the sheet to flatten it. The constantly changing lines of contact between the rolls, above as Well asbelow, prevents-any substantial marring of th polished surface, and from the point of emergence from between the two sets of rolls, the temperature is gradually reduced, so that the sheet sets and remains in almost perfectly flat condition throughout its travel through the kiln, its

In some cases, however,

temperature on emergence depending upon the length of the kiln employed, the rate of travel, and other conditions, but is preferably in the neighborhood of 200 F.

What I claim is: i

l. The process of flattening a parti-cylindrical sheet of glass which consists in moving the sheet continuously ahead endwise with its convex sides down on constantly shifting points of support, exposing the sheet to a temperature such as to cause it to partially flatten, ofits own weight, then ap plying pressure downwardly on the sheet along constantly shifting lines to further flatten it, and exposing the sheet to progressively decreasing temperatures to permit it to set as it moves along.

2. The process of flattening a parti-cylindrieal sheet of glass which consists in conveying the sheet endwise with its convex surface down through a tunnel kiln having its highest temperature at the entrance end and gradually decreasing as the outlet end. is approached and supporting the sheet upon rotating rolls, with the temperature in the kiln adjusted in the entrance portion so that the sheet approximates a flat condition of its own weight, but does not mar along the constantly shifting lines of contact with the a rotating supports, and then passing the sheet beneath a presser roll to further flatten it.

3. The process of flattening a parti-cylindrical sheet of glass which consists in conveying the sheet endwise with its convex surface down through a-tunnel kiln having its highest temperature at. the entrance end and gradually decreasing as the outlet end is approached and supporting the sheet upon rotating rolls, with the temperature in the kiln adjusted in the entrance portion so that the sheet approximates a flat condition of its own weight, but does not mar along the constantly shifting lines'ofcontactwith the rotating supports, and then passing the sheet beneath a series of presser rolls to progressively bring it to a greater degree of flatness.

, In testimony whereof, I have hereunto subscribed my name this 21st day of March, 1923,

HARRY G. SLINGLUFF. 

